Simple enough, this is a riddle thread.
Beat the previous riddle and you get to post your own. Seeing how the engraving game got out of hand, please do not post more than one riddle at a time, and please do not post another riddle until the first one has been solved or has had its answer released.

A young man spends it freely, a grown man guards it closely, an old man searches for more of it, and a dead man has none left of it. What is it?